1. Field of the Invention
The present invention relates generally to a liquid crystal display device, and more particularly to an active-matrix liquid crystal display device.
2. Description of the Related Art
In general, a liquid crystal display device includes a liquid crystal display panel having a display section which is composed of display pixels that are arrayed in a matrix. The liquid crystal display panel includes a pair of mutually opposed substrates, i.e. an array substrate and a counter-substrate, and a liquid crystal layer which is held between the paired substrates.
The array substrate includes pixel electrodes which are disposed in association with the plural display pixels. The counter-substrate includes a counter-electrode which is opposed to the plural pixel electrodes.
An OCB (Optically Compensated Bend) mode liquid crystal display device, compared to, e.g. a TN mode liquid crystal display device, has such features as a high responsivity and a wide viewing angle. Hence, the OCB mode liquid crystal display device is suited, for example, to liquid crystal TVs, the market of which is expected to steadily increase in the years to come.
In the OCB mode liquid crystal display device, when no voltage is applied to the liquid crystal layer, the liquid crystal molecules included in the liquid crystal layer are aligned in a splay alignment state which is a non-display state. When the OCB mode liquid crystal display device is activated, it is necessary to initialize the OCB mode liquid crystal display device by changing (“transitioning”) the alignment state of liquid crystal molecules from the non-display alignment state (splay alignment) to a display alignment state (bend alignment).
There has been proposed a liquid crystal display device in which a horizontal electric field is generated between neighboring pixel electrodes to facilitate, prior to displaying an image, the transition of the alignment state of liquid crystal molecules from the non-display alignment state to the display alignment state, thereby quickly displaying an image (see Jpn. Pat. Appln. KOKAI Publication No. 2002-357808).
At the time of the transition, the transition of the alignment state of liquid crystal molecules progresses most quickly in a direction opposite to the rubbing direction of alignment films which are provided on the pixels electrodes and the counter-electrode. In the above-described liquid crystal display device, however, no consideration has been given to the rubbing direction of the alignment films. Depending on a position from which the transition begins, there may be a case in which a considerable length of time is needed from when the transition begins to when the initialization is completed. In the case of a display panel with a large pixel size, a longer time may be needed until the initialization is completed.
In particular, in a low-temperature environment, the viscosity of the liquid crystal material increases, and the time that is needed for the initialization may further be increased.